/**
 * @license Copyright (c) 2003-2026, CKSource Holding sp. z o.o. All rights reserved.
 * For licensing, see LICENSE.md or https://ckeditor.com/legal/ckeditor-licensing-options
 */
import type { Editor } from '../editor.js';
/**
 * Marks the source element on which the editor was initialized. This prevents other editor instances from using this element.
 *
 * Running multiple editor instances on the same source element causes various issues and it is
 * crucial this helper is called as soon as the source element is known to prevent collisions.
 *
 * @param editor Editor instance.
 * @param sourceElement Element to bind with the editor instance.
 */
export declare function secureSourceElement(editor: Editor, sourceElement: HTMLElement & {
    ckeditorInstance?: Editor;
}): void;